Opracowanie petrograficzne osadów z Wełnowca

Stefan Cebulak, Bronisława Nurkiewicz, Maria Skupień




The present paper illustrates the results of petrographic examinations of the rocks from Namurian A, pierced in the bore hole Wełnowiec I.G. 1.
A description is presented of petrographic character of both coarse-clastic and fine-clastic deposits, and a group of rocks has been distinguished, characterized by an admixture of pyroclastic material. Moreover, there are discussed the results of studies on composition of carbonate minerals building the rocks here considered, and on heavy fraction of coarse-clastic deposits, too.
The results of the researches point to a distinct tripartition of the profile, if examined from the vivepoint of petrographical character of deposits. Such a division coincides with the tripartite division of the deposits, manly as regards their lithological anf facial features (Fig. 1) as well. The boundary of changes in character between the middle and upper series runs about 100 m below the stratigraphical boundary that divides this series into the Upper and Lower Ostrava Beds. Petrographical character of the upper series distinctly shows and increased diastrophic activity at that period, this being proved by fairly numerous intercalations of tuffite sediments. Here, the horizons of tuffite sediments are markedly convergent with the series of deposits bearing a large amount of biotite.
Under the presence of the minerals from the groups of folidoid-glauconite and of leptochlorites, the character of carbonate substance points to a more frequent occurrence of the deposits characterized by marine influences, than it might be except from palaeontological examinations.

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